Non-corrosive dry-cleaning composition



United States Patent 3,337 471 N ON-CORROSIVE DRY-CIZEANIN G COMPOSITIONSheldon G. Levy, Donald A. Baker, and Roger F. Monroe, Midland, Mich.,assignors to The Dow Chemical Company, Midland, Mich., a corporation ofDelaware No Drawing. Filed Mar. 11, 1965, Ser. No. 439,070 8 Claims.(Cl. 252'-153) The present invention relates to a novel compositionofmatter and to a process for preventing the corrosion of metals incontact therewith.

It has now been found that certain detergents used widely in thedry-cleaning of fabrics cause deterioration or corrosion of the metal incontact therewith. The marked increase in the use of dry-cleaningsolvents containing detergents which remain in the system for more thanone cycle, as well as the recent advent of the coinoperated machines,has necessitated the use of many new detergents. Due to lack of controlover and the longer retention of these detergents, a problem has arisenwhich was not foreseen, to wit: the corrosion of the metals,particularly copper, of the machines. This corrosion of copper shows upas a green coloration to the solvent system. The sales appeal islessened when the coin-operated machine customer observes this greencoloration of the solvent. Further, the corrosion is not desirable froma structural standpoint, nor from. the chance fading into (stain)light-colored clothes and fabrics.

It has now been discovered that if a small amount of a benzotriazole isdissolved in the dry-cleaning solvent system containing the detergentthe corrosion of the metal surfaces, particularly copper, is prevented,and thus the green coloration of the solvent is prevented. In accordancewith the present invention it has been found that when a benzotriazoleis added in an amount of from about 10 to 250 or more parts per millionparts of use strength or dilution solvent-detergent system the corrosionof the metal parts in contact with this system is prevented. While it isto be understood that more than 250 parts of the benzotriazole compoundcan be employed at use dilution, there is little if any advantage overthat achieved with 250 or less parts. It has been found that about 50parts of the benzotriazole compound will prevent corrosion under normalconditions as well as short periods of more severe operation. It is tobe understood that the nihibitor can be made up as a concentrate ofdry-cleaning solvent-drycleaning detergent and about 2000 p.p.m. ofinhibitor, which concentrate can be employed to prepare solvent for usein the dry-cleaning operation. The inhibitor may be added to the solventbefore the addition of the detergent, simultaneously therewith or afterthe solvent has been added. Further, it is to be understood that theinhibitor may and preferably should be replenished from time to time,particularly when fresh or makeup solvent and/ or makeup detergent isadded to the solvent-detergent system.

Ii has also been found advantageous to maintain at least 10 parts of thetriazole compound in solution at all times even after substantialdepletion of the detergent. For while it is believed that the triazolecompounds of the present invention coat out on the metal or form somecomplex which prevents attack by the corrosive detergentsolvent-moisturecombination, the coating is susceptible to loss of integrity and only ifthe solvent-detergent syswherein R represents an alkyl radical havingfrom 1 to 18 carbon atoms, n represents an integer from 0 to 4, andpreferably the total number of carbon atoms in the R's not exceedingabout 12.

The dry-cleaning solvents which are commonly employed in the industryand are compatible with the inhibitor are the chlorinated hydrocarbons,such as, for

example, perchloroethylene, carbon tetrachloride, as Well as thepetroleum naphthas, Stoddards solvent, and the like.

It is to be understood that most amine, phosphate and sulfonate-baseddetergents have been found to promote the corrosion of metals(particularly copper) by the solvent-detergent system. Representative ofthe types of detergents which have been found to be particularlycorrosive in these systems are the petroleum sulfonates, the alkylaminealkylbenzene-sulfonates, such as isopropylamine benzene sulfonate, thearyl phosphate ester-ethylene oxide adducts, alkylphenol-polyethyleneoxide adducts, nonyl phenol condensed with four to nine moles ofethylene oxide, and the ammonium dodecyl-benzene sulfonates.

The following examples illustrate the present invention but are not tobe construed as limiting.

Example 1 Nine bottles were prepared, each containing ml. of acommercial grade dry-cleaning solvent (perchloroethylene containing themanufacturers stabilizer system for the solvent). To each of threebottles was added a precleaned 2 /2 x /2" x 0.064" strip of copperweighed to the nearest 0.1 mg. To another three bottles was added alike-size strip of iron and to the final three bottles was added asimilar size strip of zinc. Each set of three bottles was furtherprepared as follows: to two of each set of three was added 2.5 percentby volume of an alkyl aryl phosphate ester ethylene oxide adductdetergent used commercially in dry-cleaning. To the third bottle of eachset of three, nothing was added. This bottle served as a check to showthe non-corrosive nature of the solvent. To one of the two bottles ofeach set to which the detergent was added, there was also added 50 partsby weight of benzetriazole per million parts by weight ofsolvent-detergent. As indicated, the other two sets of three bottlescontaining the zinc or iron strips were similarly prepared. Uponcompletion of the preparation, the nine bottles of solvent were allplaced in a constant-temperature oven held at 3 120 F. for 30 days,after which time the bottles were removed, the strips of metal cleanedand reweighed. From the loss of weight the percent loss was calculated.These data are set down in the following table:

[100 ml. perchloroethylene, 120 F., 30 days] Metal 0.. .1 Zn .1 Fe

Percent Detergent,

Wt. Diti.

Percent Vol.

Benzotriazole, p.p.m.

OOOWOOOMOWUJ Example 2 In another series of tests to further demonstratethe utility of the present invention, 0.25 volume percent of oleic acidwas added to each of three bottles containing 100 ml. ofperchloroethylene (containing the manufacturers solvent stabilizers) anda strip of copper of the same size as employed in Example I placed ineach bottle. To one jar labeled B was added 100 p.p.m. (vol.) ofbenzotriazole. To bottle B and one labelled A was added 1 percent byweight of a commercial isopropylamine benzene sulfonate dry-cleaningdetergent. The third bottle labeled C was left with only the acid,solvent and copper strip. All three bottles were placed in a constanttemperature oven held at 120 F. for 24 hours. At the end of this periodthe bottles were removed and examined visually for evidence ofcoloration. Bottle A had a green color in the liquid and the metal waspatina and greenish in color. Neither bottles B nor C had any evidenceof color and the metal remained bright and unaifected.

We claim:

1. A dry-cleaning composition containing a dry-cleaning solventstabilized against metal corrosion and solvent decomposition, adry-cleaning detergent selected from the group consisting of anionic andnonionic organic detergents and from about to about 100 parts by weightof a benzotriazole soluble in said solvent and having the formula:

wherein R represents an alkyl radical having from 1 to 18 carbon atomsand n represents an integer from O to 4.

3. Perchloroethylene stabilized against metal catalyzed deteriorationcontaining, an alkyl amine alkylbenzene sulfonate dry-cleaning detergentand from 10 to 250 parts of benzotriazole per million parts ofPerchloroethylene and detergent.

3. Dry-cleaning naphtha containing, an alkyl amine alkylbenzenesulfonate dry-cleaning detergent and from 10 to 250 parts ofbenzotriazole per million parts of naphtha and detergent.

4. Perchloroethylene stabilized against metal catalyzed deterioration,containing an alkyl amine alkylbenzene sulfonate dry-cleaning detergentand 50 parts of benzotriazole per million parts of perchloroethylene anddetergent.

5. Perchloroethylene stabilized against metal catalyzed deterioration,containing an aryl phosphate ester ethylene oxide adduct dry-cleaningdetergent and from 10 to parts of benzotriazole per million parts ofperchloroethylene and detergent.

6. Perchloroethylene stabilized against metal catalyzed deterioration,containing an aryl phosphate ester ethylene oxide adduct dry-cleaningdetergent and 50 parts of benzotriazole per million parts ofperchloroethylene and detergent.

7. A method for stabilizing a dry-cleaning solvent system containing adry-cleaning detergent selected from the group consisting of anionic andnonionic organic detergents and protecting the metal parts of themachinery used to clean fabrics and to process the detergent-solventsystem which consists of maintaining dissolved in the said system from10 to 250 parts per million parts of system of a benzotriazole havingthe formula:

References Cited UNITED STATES PATENTS 2,877,188 3/1959 Liddell 252-390XR 2,941,953 6/1960 Hatch 252390 XR 3,162,604 12/1964 Michaels 252-171FOREIGN PATENTS 582,455 9/1959 Canada.

LEON D. ROSDOL, Primary Examiner.

J. T. FEDIGAN, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,337,471 August 22 1967 Sheldon G. Levy et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3, line 52, after "weight" insert per million parts of solventdetergent Signed and sealed this 23rd day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. E.

Attesting Officer Commissioner of Patents

1. A DRY-CLEANING COMPOSITION CONTAINING A DRY-CLEANING SOLVENTSTABILIZED AGAINST METAL CORROSION AND SOLVENT DECOMPOSITION, ADRY-CLEANING DETERGENT SELECTED FROM THE GROUP CONSISTING OF ANIONIC ANDNONIONIC ORGANIC DETERGENTS AND FROM ABOUT 10 TO ABOUT 100 PARTS BYWEIGHT OF A BENZOTRIAZOLE SOLUBLE IN SAID SOLVENT AND HAVING THEFORMULA: